Method and means for preventing electrolytic action



March 31, 1931. H. CHRISTOPHERSEN 1,798,305

METHOD AND MEANS FOR PREVENTING ELECTROLYTIC ACTION .3 SheetsSheet lFiled Sept. 29. 1927 March 3l, 1931. H. CHRISTOPHERSEN 19793,:395

METHOD AND MEANS FOR PREVENTING ELEGTROLYTIC ACTON Filed sept. 29, 1927Sweets-sheet 2 W5. v W 7 /y y Z5 '/NVENTo/efwww [NVENTOR A TTORNEY H.CHRHSTPHERSEN METHOD AND MEANS FOR PREVENTIHG ELEGTROLYTIG ACTION FiledSept. .'5 Sheets-Sheet 3 March 31, 193,11.

Patented Mar. 31, 1931 UNITED YSTATES PATENT OFFICE HERBERTCHRISTOPHERSEN, 0F EAST ORANGE, NEWJERSEY, ASSIGNOR TO REVERE RUBBERCOMPANY, OF CHELSEA, MASSACHUSETTS, A CORPORATION OF RHODE ISLAND METHODAND MEANS FOR PREVENTING ELECTROLYTIC ACTION f Application led September29, 1927. Serial No. 222,916.

This invention relates to an improved method of and means for protectingparts from electrolytic action. More particularly it relates to animproved method for sealing the ends of a rubber sleeveupon a shaft, rodor similar part whereby water is excluded from the part, and to theresulting article.

This application is a continuation in part of my co-pending applicationSerial No. 139,251, filed October 4, 1926.

A serious diliiculty in the use of propeller shaft assemblies has beenthat by reason of electrolytic action, the shaft assembly members, suchas shafts, struts, etc., quickly become pitted and weakened, and thisaction is particularly rapid at points where the member is in directcontact with a dissimilar metal. The shafts are ordinarily made of steeland provided with bearing sleeves of bronze or similar metal, whichsleeves are disposed in the bearings within the stern tubeof the vessel.Itis impossible to prevent the leakage of water through the bearingsinto the stern tube, and as a result, the above described electrolyticaction takes place within the stern tube.

An obJect of the invention is to provide a protective coating forpropeller shafts and other members such as struts or braces which willprevent access of water to the same and thereby avoid electrolyticaction. Another object is to provide a permanent and water tight unionat the ends of the protective coating. Other objects will appear fromthe detailed disclosure.

Referring to the drawings:

Fig. 1 is a perspective view of the propeller and the propeller guard ofa ship with parts of the stern of the ship broken away to show the shaftand bearings therefor in transverse section;

Fig. 2 is a side elevation of the propeller shaft with parts thereofbroken away and in section;

Fig. 3 is a cross-section taken on the line 3-3 of Fig. 2;

Fig. 4 is a front elevation of one forni of band for gripping the rubbertube;

Fig. 5 is a side elevation of the band;

Fig. 6 is a front elevation of the band showing the fastening means forthe end of the band;

y Fig. 7 is a front elevation of a modification of the band;

Figs. 8 and 9 are perspective views of the fastening elements for themodified band;

Fig. 10 is a side elevation of a rubber covered strut prior tovulcanization;

Fig. 11 is a section upon the line 11-11 of Fig. 10 showing the rubbercovered strut subsequent to vulcanization; Y

Fig. 12 is a detail side eleva-tion of a strut with parts broken awayand illustrating the manner of assembling the sleeve upon the strut; andt Fig. 13 is a section upon the line 13-13 of Fig. 1l.

Referring to the drawings, and particularly to Figs. 1-9 inclusive,reference numeral 1 designates the stern of a ship in which is rigidlysecured the propeller shaft assembly members comprising the stern tube 2which is held in position by shoulders 3, t and 5 which engage the wallsof the ship. An inboard bearing sleeve 6 made of suitable material suchas bronze is secured Within the stern tube together with an aft or sternbearing 7 which is formed for example of lignuin vitae. The sternbearing 7 is enclosed in a bronze housing 8. Both the housing 8 and thestern bearing 7 abut against a shoulder 9 upon the stern tube 2. A coverplate 10 formed of bronze or other suitable material overlies theirouter end portions. Extending through the inboard and stern bearings inspaced relation to the stern tube is the propeller shaft 11 whichcarries rigidly secured thereto composition bearing sleeves 12 at thoseportions which contact with the bearings 6 and 7. The compositionbearing sleeves 12 may be made for exampleof brass or bronze andordinarily are secured to the shaft 11 by shrinking them thereon. Theouter end of the shaftll is tapered at 13 and a propeller wheel 14 isheld thereon by means of a nut 15 which is threaded on tothe end of theshaft.

Leakage of water commonly occurs through the stern bearing and the wateraccumulates between the stern tube and the (ill propeller shaft.Electrolytic action results, causing rapid deterioration of thepropeller shaft, usually most rapid at the portions immediately adjacentthe bearing sleeves 12. In order to exclude the water between the sterntube and propeller shaft from direct contact with the shaft and therebyprevent pitting of the shaft caused by electrolytic action, a sleeve 11of rubber composition is formed about thehshaft completely coveringsame, and it is particularly desirable that the ends of the sleeve betightly and permanentlyv secured.

The bearing sleeves 12 are so formed at their adjacent ends as tofacilitate the connection thereto of the rubber sleeve in a permanentand water tight manner. Each sleeve 12 is provided with a reducedextension in the form of steps 15 and 19, which steps are providedrespectively with the annular grooves 17 and 20. Between the step 19 andthe main body of the sleeve, a shoulder 21 is formed which is preferablya vertical one, while between the steps 15 and 19 and at the end of thestep 15 there are formed the respective bevelled or inclined shoulders13 and 16. The number and size of these stepped portions may be variedas desired.

Instead of the annular recesses 17 and 20, a plurality of localizedrecesses which do not extend entirely around the sleeves 12 can beprovided.

In the operation of encasing the shaft 11 with rubber composition, oneor more coatings of rubber cement, either vulcanizable orunvulcanizable, are applied to the shaft and a strip of the compositionof the approximate thickness of the shoulder 16 is wrapped around thesame to form a tube or sleeve 22 of approximately the same thickness asthe extension 15 with the ends of the sleeve abutting the shoulders 16.The tube 22 is rolled and stitched into intimate contact with thecemented shaft. A band 23 of metal is se cured around the rubber tube 22adjacent each end thereof and if desired at intervals throughout itslength to clamp the tube to the shaft 11. The band is provided with aplurality of perforations 25 which may be transversely elongated orotherwise shaped as desired. In its preferred embodiment the band is cutaway adjacent one end to form an elongated slot 26 with arms 27 ateither side thereof. The end of the band is bent back upon itself atabout the middle portion of the arms 27 and secured to the body of theband by the rivet 2S, thus forming loops 29. Adjacent its opposite endthe band is cut away at the sides to leave a connecting tongue 30 in themiddle thereof, which is of a width to fit within the slot 26. This endof the band is bent back upon itself at the middle of the tongue and arivet secures it to the band leaving a loop 31. lVhen securing the tubeof rubber composition to the shaft the band is wrapped around it withthe loop 31 fitting between the loops 29. A wedge 32 is then driventhrough the loops and serves to draw the ends of the band togetherthereby tightening the band in place. lVhen a wedge is used ofsufficient length to protrude from the loops 29, the ends can be bentback to function as locking means to prevent the wedge from slippingloose.

Iaving secured the rubber tube 22 in position, a second strip of rubbercomposition of a thickness about equal to that of the shoulder 18 iswrapped around the rubber tube 22 to form the tube 33, the ends of whichoverlie the steps 15 and abut the shoulders 18. The tube 33 ispreferably rolled and stitched into place. A metal band 23 is positionedover the tube opposite the annular groove 17 and is clamped in position.In the embodiment illustrated in the drawings a third tube V 3st ofrubber composition of a thickness less than that ofthe shoulder 21 isplaced over the tube 33 and step 19 is preferably rolled and stitched,and is secured in place by a band 23. Narrow tapering strips 457 ofrubber composition are wrapped around the ends of the outer bandabutting against the shoulders 21 and terminating substantially flushwith the surfaces of sleeves 12. Preferably cement is applied to thesteps 15 and 19 before applyine` the rubber sleeves 33 and 34e.

The pressure which is applied to the band 23 when driving the wedge 32into place is preferably sullicient to cause A[low of the rubbercomposition into perforations 25 and into the grooves or recesses 17 and20. Vulcanization causes complete flow of the rubber into the same sothat the completed sleeve of rubber contains the rings embedded thereinwith projections of rubber passing both through the perforations andinto the grooves, and the cement bonds the rubber to the metallic parts.

The rubber tubing is made of a composition suitable to withstand thevibration and .Xposure to water to which it is subjected. Such acomposition can consist of the following ingredients:

Parts by wright Rubber 100 Zinc oxide 2 Lamp black 35 Dibenzylamine 11/2Sulphur 11/2 cent the shaft can be made of hard rubberl composition.Vulcanization unites -the plies into a unitary sleeve of rubbercomposition. In some cases it may be advantageous to roughen, plate, orotherwise treat the shaft to obtain a satisfactory foundation for therubber composition.

A modified form of band is shown in Figs. 7, 8 and 9 in which a band 36is provided with closely spaced transversely extending slots 37. Thisform of band can be made in long strips and cut to size as needed, andfastening means secured to the ends. The fastening means for the ends ofthe band consist of separate clips one of which 38 comprises a bodyportion from which projects a lug 39 bent to engage a slot 37 of theband and thereby hold the clip securely to the band. The opposite end ofa clip 38 is provided with two projecting arms 40, the ends of which arebent about themselves to form locking lugs 41. rlhe other clip 42 isprovided with a bent lugv43 for engaging a slot 37 in the band wherebyit is secured thereto. From the opposite end of the clip there projectsan arm 44 of a size adapted to fit between the arms 40. A bent-over endupon the arm 44 constitutes a locking lug 45. Upon positioning the band36 with clips 38 and 42 around the rubber tube a Wedge 32 (see Fig. 6)is driven into the slots formed between arms 40 and lugs 41 and arm 44and lug 45 thereby drawing the parts together.

When the sleeve of rubber composition is to be applied to a member ofnon-cylindrical shape, such for example as a rod which is rectangular,ovoidal, or otherwise curved or shaped in cross section and which hasrelatively sharp edges or margins, the edged portion of the rod ispreferably provided with a recess wider than the width of the clampingband which is to be used to grip the sleeve to the rod. Such aconstruction is shown in Figs. 10 to 13 inclusive in which there isshown a strut 50, such as can be used in bracing and supporting apropeller shaft to the side of a ship. The strut terminates in anenlarged portion at one end which is so shaped as to form a retaininghub 51 for the propeller shaft. The opposite end of the strut isenlarged and suitably flanged so that a water tight connection can beformed with the plating 52 of the ship. The strut is generally oval inshape as can be seen in Fig. 11, being given a stream line contour whichis gradually enlargedtoward one side and tapers toward a relativelysharp edge at-the opposite side. The ends of the strut adjacent the hub51 and the plating 52 are enlarged gradually, as can be seen fromV aninspection of Fig. l0. The sleeve of rubber composition is preferablyapplied over the entire surface which is exposed to electrolytic action.Before applying the sleeve, the edged side of the strut is provided witha plurality of spaced recesses indicated as 53.

The base of each recess extends generally parallel with the surface ofthe opposite side of the strut. The recesses at the ends of the strut,which recesses are positioned in the gradually enlarged portion of thestrut, are made sufficiently wide to receive two or more clamping bandsin side by side relation and the base of these recesses is madegenerally parallel with the first mentioned recesses. The thickened sideof the strut can also be recessed at the enlarged tapered end of thestrut, as shown at 54, and the base of this recess is formedapproximately parallel with the general extent of the strut. Therecesses are made suficiently deep in the strut and are given a contoursuch that when the clamping bands are positioned in the recesses and aredrawn tightly around the strut, the tendency of the bands to cut intothe sleeve of rubber composition due to the edged and tapered shape ofthe strut, is eliminated.

ln building up the sleeve, the surface of the strut is preferablycleaned in any way which may be desirable and one or more coatings 55 ofrubber cement are preferably applied thereto. A tube 56 of rubbercomposi tion is formed around the strut and is rolled and stitched intointimate contact with the recessed and cemented strut. 'Clamping bands57, either perforated or unperforated, are positioned around the tube 56passing through the recesses 53 and 54 and are drawn togethersufficiently tightly by means of the wedge 58 to cause flow of therubber composition into the perforations of the clamping band. The smallend of the wedge is then bent back over the band to lock the connection.The recesses 53 and 54 are now filled in with a body 59 of rubbercomposition forming a continuous unrecessed coating of rubbercomposition over the strut. A second tube 60 of rubber composition isthen assembled around the strut and is rolled and stitched into place.Vulcanization is now effected under such conditions as are required forthe particular rubberV composition used forming a solid sleeve 61 ofrubber composition intimately united to the strut and carrying aplurality of clamping bands embedded therein.

While the invention has been described with particular reference to itsapplication to propeller shaft assembly members such as shafts orstruts, it is obvious that it can be applied to any type of rod or pipewhich is to be subjected to electrolytic or other destructive orcorrosive action. A waterproof insulating sleeve with its connectingmeans such as has been described would be of special advantage, ifsuitably protected, when applied to a pump rod. In place of a metal bandfor holding the sleeve in place there can be substituted a band made ofany material which will grip the sleeve to a'shaft. Unperforated bandscan be used if desired as well as bands o f varying degrees of'width.

By the apparatus just described there has been formed a member whichWill have a prolonged life When surrounded by Water. The rubber sleevesor coatings completely surround. the propeller shaft assembly mem- -bersand prevent any access of Water thereto, thereby obviating anyelectrolytic action. However, due to Whipping of the propeller i shaft,expansion and contraction, and other Cil causes, the ends of the rubbersleeve are liable to become loosened, thereby allowing access of Waterto the shaft at the very points Where electrolytic action is mostsevere, that is, Where the ends of the bronze bearing sleeves 12 meetthe steel shaft. By the connection herein disclosed, a permanent andWater tie-ht connection for the rubber sleeve is provided at thesepoints, and as the reinforcing bands used are completely emb-edded inthe rubber composition, they are not subject to deterioration such aswould occur if they Were on the exterior of the sleeve and in contactwith Water.

It is to be understood that the invention is not limited to theparticular method of vulcanization set forth. The use of a rubbercomposition vulcanizable through the agency of carbon disulphide hasbeen found satisfactory, but it is evident that the composition and themeans for vulcanizin the same may be considerably varied Without depa`ting from thx spirit of the invention as defined in the appended claims.

Having thus described my invention, what l claim and desire to protectby Letters Patent is:

l. As an article of manufacture, a propeller shaft assembly member, acoating of rubber composition carried by the member, and a clamping bandembedded in the coating and encircling the member, said band beingprovided with means adapted to tighten it around said member.

As an article of manufacture, a propeller shaft assembly member providedwith a recess, a coating of rubber composition carried by the member, arib of rubber composition integral with the coating projecting into therecess, and a clamping band embedded in the coating und encircling themember.

3. As an article of manufacture, a pr peller shaft assembly memberprovided With a recess, a sleeve of rubber composition encircling` themember. a rib of rubber composition integral With the sleeve projectinginto the recess, and a clamping band embedded in the sleeve opposite therecess.

4. As an article of manufacture, a member provided with an annularrecess, a sleeve of rubber composition encircling the member, an annularrib of rubber composition carried by the sleeve and projecting into therecess, a perforated clamping band embedded in the sleeve, and ribs ofrubber composition inteeveaeos gral with the sleeve extending into theperforations of the band.

5. As an article of manufacture, a member provided with a recess in itssurface, a sleeve of rubber composition encircling the member, a ribcarried by the sleeve and engaging the recess, a perforated clampingband embedded in and gripping the sleeve, and projections of rubbercomposition integral with the sleeve extending into the perferations.

6. As an article of manufacture, a propeller shaft assembly member, asleeve of rubber composition encircling the member, and a plurality ofclamping bands embedded in the sleeve at varying radial positions.

7. As an article of manufacture, a member, a sleeve of rubbercomposition encircling the member, a plurality of perforated bandsembedded in the sleeve at varying radial positions, and projectionscarried by the sleeve extending through the perforations.

8. As an article of manufacture. a pro` peller shaft assembly memberprovided with an enlarged portion, said enlarged portion being recessed,a sleeve of rubber composition encircling the member and overlapping theenlarged portion, a rib of rubber com position integral with the sleeveand projet-ting into the recess, and a clamping band embedded in andgripping the sleeve opposite the recess.

9. As an article of manufacture, a propeller shaft assembly memberhaving an enlarged portion, a sleeve of rubber composition encirclingthe member and abutting a portion at least of the enlarged portion, aperforated band gripping the sleeve against the member and projectionson the sleeve extending into the perforations.

l0. As an article of manufacture, a member having a recessed enlargedportion, a sleeve of rubber composition encircling the member, aperforated band embedded in and gripping the sleeve opposite the recess,and projections on the sleeve extending into the recess and into theperforations of the band.

ll. As an article of manufacture, a member provided With a plurality ofenlarged p rtions in stepped relation, a sleeve of rubber compositionencircling the member and at least some of the enlarged portions, andclamping bands gripping the sleeve opposite the enlarged portions.

1Q. As an article of manufacture, a propeller shaft assembly memberhaving an e lged portion, said edged portion being provided With arecess, a coating of rubber composition carried by the member andextending into the recess, and a clamping band gripping the coating tothe member, said clamping band passing through t-he recess and embeddedin said rubber coating.

13. As an article of manufacture, a propeller shaft assembly memberhaving an edged portionsaid edged portion being proyvided `with arecess, a coating of rubber compositioncarried bythe `member and fillingthe recess, and a clamping band gripping the coating to the member, saidclamping band passing through the recess and embedded in said rubbercoating.

14.-. As an article of manufacture, a propeller shaft assembly memberhaving an edged portion, said edged portion being provided With'arecess, a coating of rubber composition carried by the member, and aclamping band embedded in the rubber composition and encircling themember passing through the recess. l

15. As an article of manufacture, a member having a gradually enlargedand edged portion, said edged portion being provided with a recess, acoating of rubber composition carried by the member and a plurality ofclamping bands embedded in the rubber composition and encircling themember passing through the recess in side by side relation.

16. As an article of manufacture, a member having an edged portion, saidedged por- 'tion being provided with a recess, a coating of rubbercomposition carried by the member and a plurality of clamping bandsgripping the rubber composition and en-n circling the member passingthrough the recess in side by side relation.

17. As an .article of manufacture, a member having an edged portion,said edged portion being recessed, a coating of rubber compositioncarried by the member, and a clamping band gripping the coating tosaidmember, said clamping band passing through the recess and embeddedin the coating.

18. A propeller shaft assembly member having a gradually enlarged edgedportion, said enlarged edged portion being recessed, a coating of rubbercomposition carried by the member, and a clamping band embedded in thecoating and passing through the recess.

19. A propeller shaft assembly member having a gradually enlargedportion, said enlarged portion being provided With a re cess the base ofWhich extends parallel With the extent of the member, a coating of rubber composition carried by the member, and a clamping band embedded inthe coating and passing through the recess.

20. The method of protecting from electron lytic action a plurality ofadjoining members composed of dissimilar metals, which consists incovering the members with a sleeve of rubber composition havingincorporated bands adapted to clamp the sleeve around the members.

21. The method of protecting Va member exposed to electrolytic actionwhich com prises forming a recess in the member, dis posing a sleeve ofrubber composition around the member, clamping the sleeve opposite therecess with a band with sufficient pressure to cause a portion of thesleeve to be projected into the recess, encasing the band with a secondsleeve of rubber composition, and vulcanizing.

22. The method of protecting a member lforming a recess in the member,applying rubber cement to the member, disposing a sleeve of rubbercomposition around the member, clamping the sleeve oppositeV the recessWith a perforated band With sufficient pressure to cause a portion ofthe sleeve to project into the recess and perforations, encasing theband with a second sleeve of rubber composition and vulcanizing.

24. The method of protecting from electrolytic action a plurality ofadjoining members composed of dissimilar metals, which comprisesapplying rubber cement to the members, forming a sleeve of rubbercomposition around the members, clamping the sleeve with a band aroundeach member, encasing the bands with rubber composition, andvulcanizing. j

25. A method of securing a sleeve of rubber composition to a memberprovided with a plurality of progressively enlarged portions Whichcomprises forming grooves in the enlarged portions, coating the memberwith rubber cement, applying a sleeve of rubber composition to -thecemented member in abutting relation to the end of one of the enlargedportions, clamping the sleeveivith a band, placing a sleeve of rubbercomposition over 'the lirst mentioned sleeve and extending upon theadjoining enlarged portion, clamping the second sleeve With a band tothe last named enlarged portion, placing a sleeve of rubber compositionover the second mentioned band, and vulcanizing.

26. A method of securing a sleeve of-rubber composition to a memberprovided With a plurality of progressively enlarged portions vvhichcomprises coating the member With rubber cement, disposing a sleeve lofrubber composition of the approximate thickness of one of the enlargedportions upon the cemented member in abuttingrelation to one of theenlarged portions, clamping the sleeve to the member with a band,encasing the sleeve With a second sleeve .of rubber composition, thesecond sleeve overlying the next adjoining enlarged portion, clampingthe Sleeve With a band opposite the enlarged portion, encasing the lastmentioned band with a sleeve of rubber composition, and vulcanizing.

27. The combination with a propeller shaft assembly including bearingsleeves mounted upon the shaft, of a covering of rubber compositionadhesively connected to the shaft and the sleeves and adapted to preventcommunication of water between said shaft and the sleeves, and retainingbands embedded in the rubber composition.

28. The combination with a propeller shaft assembly including bearingsleeves mounted upon the shaft, of a covering of rubber compositionadhesively connected to the shaft and the sleeves and adapted to preventcommunication of water between said shaft and the sleeves, said bearingsleeves being provided with annular reduced portions in the form ofsteps over which the ends of the rubber covering extend, said stepshaving de-- pressions in which the covering is anchored.

29. The combination with a propeller shaft assembly including bearingsleeves mounted upon the shaft, of a covering of rubber compositionadhesively connected to the shaft and the sleeves and adapted to preventcommunication of water between said shaft and the sleeves, said bearingmembers being provided with annular reduced portions in the form ofsteps over which the ends of the rubber covering extend, and retainingbands embedded in said rubber covering around said steps.

30. The combination of a propeller shaft assembly including bearingsleeves mounted upon the shaft, a covering of rubber compositionadhesively connected to the shaft and the sleeves and adapted to preventcommunication of water between said shaft and the sleeves, said bearingmembers being provided with annular reduced portions in the form ofsteps over which the ends of the rubber covering extend, said stepsbeing provided with annular grooves, and retaining bands embedded insaid rubber composition over said grooves.

31. A propeller shaft assembly including a shaft and bearing membersecured thereto, said bearing members being reduced to form a pluralityof annular steps of successively decreasing diameters, and a pluralityof layers of rubber composition placed one upon another around saidshaft and having the ends thereof respectively covering the successivesteps of the bearing members, the rubber composition being adhesivelyunited to the shaft and the bearing members and vulcanized together toform a unit.

32. The combination with a propeller shaft assembly including a bearingsleeve mounted upon the shaft-of a covering of rubber compositionsurrounding the shaft and overlapping the bearing sleeve, said coveringbeing adhesively united to the shaft and the bearing sleeve, and aclamping element for holding the overlapping portion of said covering inintimate contact with the bearing sleeve.

33. The combination with a propeller shaft assembly including a bearingsleeve provided with an annular groove, of a covering of rubbercomposition surrounding the shaft and overlapping the bearing sleeve andprovided with a bead fitting into said groove, said covering beingadhesively united to the shaft and the bearing sleeve, and retainingbands associated with said covering and forcing the bead into theannular groove.

34. The method of protecting from electrolytic action a propeller shafthaving a bearing member thereon, which consists in covering the shaftwith a sleeve of rubber composition, extending the end of said sleeveover the end of the bearing member, adhesively connecting said sleeve tothe shaft and the bearing member, reinforcing said sleeve With retainingbands adapted to encircle the shaft and the bearing member, andvulcanizing the whole to form a unit.

35. In combination, a shaft, a bearing sleeve, and a waterproof coveringover the shaft and the bearing sleeve, said sleeve having an annulargroove in which the waterproof covering is anchored.

3G. In combination, a shaft, a bearing sleeve, and a waterproof coveringover the shaft and the bearing sleeve, said sleeve having an annulargroove, and bands arranged to hold the covering anchored in the groove.

Signed at New York, county and State of New Yori, this 28th day ofSeptember, 1927.

HERBERT CHRISTOPHERSEN.

